Music based on the Western scale utilizes the twelve different tones or notes in the Western scale, which repeat in cycles or "octaves". The common names for these twelve notes are: A, A# or Bb, B, C, C# or Db, D, D# or Eb, E, F, F# or Gb, G, G# or Ab. There is a fixed distance between every note and its predecessor (or successor) in the scale, referred to as a semitone. Thus, travelling up the scale, the note E is always the same distance (of four semitones) from C (within any particular octave). Since the displacements between every successive note (in a chromatic scale) are the same, different pairings of notes may share equivalent relative displacements. For example, G is also four semitones above D# (as is E above C).
Combinations of these twelve notes are grouped together following accepted Western tonal conventions to form scales (commonly, "major" or "minor" scales) based on and commencing with a main or root note. Accordingly, each type of scale (eg. major or minor) has twelve different tonally distinct variations, each based on a different root note. Generally, works or passages of music are based on these different scales, which are designated through the use of "key signatures".
In music, the key signatures, or more simply the "keys" may change frequently, both within a single piece of music, and between one piece and the next. Following the performance of music in a first key, the audience's ears will have become tuned to that key. With an immediate change to a new key, the music in the new key will typically sound discordant until the listeners' ears have become attuned to the new key. Where different pieces of music are intended to be heard separately and a distinct pause is provided between pieces of music, this is not a problem. However, often it is desirable to have one piece of music flow directly into a following piece, and if the keys of the two pieces are different, this can sound harsh or discordant to a listener.
A technique known as "bridging" or "modulating" is known for gradually transitioning the listener's ears from one key to another. Bridging typically involves the use of a progression of chords which lead the listener from the first key to establish the new key. Bridges often include chords which are common to both keys. Bridges are commonly used when the key signature changes within a single piece of music. Bridges can also be used to transition from one piece of music to a second piece of music in a different key.
In a live performance of music, frequently one piece of music will follow another which has been written in a different key. In order to avoid providing a reasonable pause, otherwise required so that the second piece of music does not sound discordant to the audience, the performers will typically have to develop a bridge to provide a smooth transition in the music from the first key to the new key. The process of creating an appropriate bridge requires skill and musical creativity and can be a time-consuming and difficult task, particularly for novice musicians.
Prior art techniques are known for providing a bridge between one key signature and another. However, the prior art includes a bridge specifically prepared for each specific key to key transition. Since there are twelve different key signatures, each of which can bridge to one of the other eleven key signatures, the prior art requires one hundred and thirty-two different prepared bridges, which can be referenced for the specific key change. This prior art technique provides only a single chord progression for each specific key transition.
There is accordingly a need for systems and methods which make it easier and more efficient for musicians to prepare a musical bridge from one key to another.